Welcome @kadjur. I would suggest you continue to seek an answer to these symptoms. An MRI might be the solution, but I am not a doctor.
In moments of symptom shrugged shoulders in the past I would assure the doctors that we could probably find out what is going on with an autopsy. That statement usually gets the ball rolling.
You are your own best healthcare advocate. Keep at it.

Hello,
My post chemo/radiation treatments left me with thick mucus.
OTC recommended products did not work!

Here’s the thing that works for me; first thing in the morning and several times during the day swish hot water, sip/swallow and hack until all is clear then brush with regular toothpaste and then prescription toothpaste.

As for the lump and trouble swallowing; an ENT and family doctor missed my stage IV cancer twice and my dentist found it!

Maybe a CATCT should be done?

If it’s just a restriction they can stretch the area as I have had that done a few times.

MOJO

Hello @kadjur. My experience with head and neck cancer included radiation that left me with ulcers on my tongue and very painful. At one point I developed a fungal infection of the tongue surface that caused pain and burning and the feeling of a thick hairy surface. It was quickly remedied with medication. You may be prone to infection due to the reduced, thickened saliva. I would suggest a consultation with your ENT to also include discussion of why you still feel a lump in your tongue. Perhaps more diagnostics are needed. Referral to a major cancer or referral center is always a great way to go. I had an excellent experience at Mayo Rochester with their ENT department. We still drive 10 hours to Mayo for rechecks 11 years later. Good luck to you.